Dentinogenic Ghost Cell Tumor in a Sumatran Rhinoceros

An adult female Sumatran rhinoceros was observed with a swelling in the left infraorbital region in March 2017. The swelling rapidly grew into a mass. A radiograph revealed a cystic radiolucent area in the left maxilla. In June 2017, the rhinoceros was euthanized. At necropsy, the infraorbital mass measured 21 cm × 30 cm. Samples of the infraorbital mass, left parotid gland, and left masseter muscle were collected for histopathology (Hematoxylin & Eosin, Von Kossa, Masson’s trichrome, cytokeratin AE1/AE3, EMA, p53, and S-100). Numerous neoplastic epithelial cells showing pleomorphism and infiltration were observed. Islands of dentinoid material containing ghost cells and keratin pearls were observed with the aid of the two special histochemistry stains. Mitotic figures were rarely observed. All the neoplastic odontogenic cells and keratin pearls showed an intense positive stain for cytokeratin AE1/AE3, while some keratin pearls showed mild positive stains for S-100. All samples were negative for p53 and S-100 immunodetection. The mass was diagnosed as a dentinogenic ghost cell tumor.

Variations in Aggressive and Indolent Behaviour of Central Dentinogenic Ghost Cell Tumor

Among the aggressive odontogenic tumors, a few tumors generally ameloblastomas, carry a connotation of being aggressive. But, a rare tumor like central dentinogenic ghost cell tumor (DGCT) can be equally aggressive with a propensity for recurrence. The two cases discussed in this article are divergent in behaviour with features such as presentation, seen in early decades as central intraosseous tumors in the maxilla and mandible. The first case describes an aggressive DGCT, associated with impacted tooth and odontome which showed recurrence into a large solid tumor within a year. The second case arose in accordance with a partially erupted molar which was comparatively innocuous and less aggressive. Both the cases exhibited classic histopathological features. These two unconventional cases of DGCT with a follow-up are being reported here to highlight the variation in behaviour and presentation and also to understand the aggressive nature of the tumor.